Product of Array Except Self
A medium-tier problem at 68% community acceptance, tagged with Array, Prefix Sum. Reported in interviews at Asana and 41 others.
Product of Array Except Self is asked by 42 companies, including Nvidia, Intuit, Disney, and Asana. It's a medium-difficulty array problem with a 68% acceptance rate, which means it's hard enough to separate candidates but common enough that you'll face it. The trap is obvious: multiply all numbers and divide by each element. That fails on zeros and reveals you haven't thought about the constraint. The real solution uses prefix and suffix products to avoid division entirely. If you hit this problem cold during an assessment and blank on the pattern, StealthCoder surfaces a working solution in seconds, invisible to the proctor.
Companies that ask "Product of Array Except Self"
Product of Array Except Self is the kind of problem that decides whether you pass. StealthCoder reads the problem on screen and surfaces a working solution in under 2 seconds. Invisible to screen share. The proctor sees nothing. Made by a working FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know.
Get StealthCoderThe problem forces you past the naive division trick by either including zeros or explicitly disallowing it. You build two pass arrays: one storing the product of all elements to the left, another storing the product of all elements to the right. Then multiply them together. It's elegant but not intuitive if you haven't seen Prefix Sum patterns before. Most candidates waste time on the division approach, then realize they're stuck. The gotcha is handling the space constraint: a one-pass solution exists if you're careful with indexing. Interviewers test whether you know Prefix Sum as a technique and can adapt it. If this problem appears in your live OA and the division angle doesn't click, StealthCoder runs invisibly and hands you the prefix-suffix logic without you leaving the editor.
Pattern tags
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Make sure you actually pass it.
Product of Array Except Self recycles across companies for a reason. It's medium-tier, and most candidates blank under the timer. StealthCoder is the hedge: an AI overlay invisible during screen share. It reads the problem and surfaces a working solution in under 2 seconds. Made by a working FAANG engineer who treats the OA the way companies treat hiring: as a game with rules you should know. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Product of Array Except Self interview FAQ
Is this problem still asked at FAANG?+
Yes. Nvidia, Intuit, and Disney are in the top companies asking it. Asana also reports it. It's stable across 42 total companies, so it's not going away. Medium difficulty and high acceptance rate mean many candidates see it as passable, which makes it a common screening filter.
What's the trick everyone misses?+
Division. You can't divide by zero, and that breaks the obvious solution. The real trick is Prefix Sum: build left and right product arrays, then combine them. No division, no edge case disasters. The pattern generalizes to many array problems.
Can I solve it in one pass without extra arrays?+
Yes, but it requires careful indexing and space optimization. You output to the result array first, then backfill. It's cleaner in interviews to use two passes for clarity unless asked to optimize space. Interviewers care more that you know the Prefix Sum pattern than that you micro-optimize.
How does Prefix Sum relate to this problem?+
Prefix Sum is about precomputing cumulative values to answer range queries in O(1). Here, you precompute products to the left and right of each index. It's a direct application. Understanding Prefix Sum unlocks dozens of array problems.
What if the array has zeros?+
That's why the problem doesn't allow division. If there's one zero, all positions except that index are zero. If there are two or more, the entire output is zero. Your prefix-suffix solution handles this naturally without branching logic.
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